The present invention relates to a composite material made up from reinforcing fibers embedded in a matrix of metal, and more particularly relates to such a composite material utilizing a mixture of potassium titanate whiskers and short fiber type material as the reinforcing fiber material, and a light metal as the matrix metal, i.e. to a partially potassium titanate whisker reinforced composite material.
Further, the present inventors wish hereby to attract the attention of the examining authorities to copending U.S. patent application Ser. Nos. 734655, 735068, 734654 now U.S. Pat. Nos. 4,601,956 and 4,664,704 and 4,595,638 respectively, and Ser. No. 901196, which may be considered to be material to the examination of the present patent application.
Previous research relating to composite materials incorporating reinforcing fibers has evolved the ideas of utilizing as such reinforcing fiber material such materials as silicon carbide whiskers, silicon nitride whiskers, alumina short fibers, crystalline alumina-silica short fibers (aluminia-silica short fibers including mullite crystals), and amorphous alumina-silica short fibers. Such concepts are mulled in, for example, the specifications of Japanese patent application Ser. Sho. Nos. 60-120786 (1985), Sho. 60-120787 (1985), Sho. 60-120788 (1985), Sho. 60-193415 (1985), Sho. 60-19793 (1985), and Sho. 60-24539 (1985), corresponding to U.S. application Ser. No. 868,542, filed May 30, 1986; Ser. No. 868,750, filed May 30, 1986; Ser. No. 868,541, filed May 30, 1986; Ser. No. 895,811, filed Aug. 12, 1986; Ser. No. 007,790, filed Jan. 28, 1987; and Ser. No. 011,924 filed Feb. 6, 1987, respectively, among others, all of which Japanese patent applications were filed by an applicant the same as the applicant of the parent Japanese patent application of which Convention priority is being claimed for the present patent application, and none of which above identified documents is it hereby intended to admit as prior art to the present patent application except to the extent in any case otherwise mandated by applicable law. And, utilizing such above identified short fiber materials as reinforcing fiber material, in said publications, for example, there have been disclosed efforts to fabricate composite materials having enhanced strength and wear resistance, as well as other desirable properties.
Further, as described, for example, in pages 66 through 71 of Vol. 8, Issue 2 of the Publication of the Japanese Composite Material Assocation for 1982, potassium titanate whiskers are per se known and are a short fiber material; and in some cases attempts have been made to utilize such potassium titanate whisker as reinforcing material for composite materials which are to be reinforced with fibrous material.
However, with regard to composite materials utilizing as reinforcing fiber material such fiber materials as identified above, i.e. utilizing as reinforcing fiber material silicon carbide whiskers, silicon nitride whiskers, alumina short fibers, crystalline alumina-silica short fibers, or amorphous alumina-silica short fibers, alothough they have admirable and intriguing properties at room temperature, they are fraught with the basic disadvantage that their strength is considerably deteriorated at higher temperatures such as at temperatures around about 250.degree. C. Consequently, application of such fiber reinforced composite materials to high temperature applications has been impracticable.